The temperature of absolute zero is defined as 0 Kelvin (0 K). Absolute zero is the lowest possible temperature in the Kelvin scale, where all molecular motion theoretically ceases. It corresponds to -273.15 degrees Celsius or -459.67 degrees Fahrenheit.
Absolute zero is defined as 0 K because the Kelvin scale is based on the properties of gases and the behavior of ideal gases at low temperatures. At absolute zero, the kinetic energy of particles is minimized, and their motion comes to a complete stop. This definition allows for a temperature scale that does not have negative values, making it mathematically convenient for scientific calculations and comparisons.
Setting absolute zero as a temperature of 0 K ensures that temperature is always a positive value or zero. It avoids the introduction of negative values, which could complicate calculations and lead to ambiguities. Additionally, it aligns with the behavior of gases, as the volume of an ideal gas theoretically approaches zero as the temperature approaches absolute zero.
Negative infinity K would not be a suitable choice for the definition of absolute zero because it would not provide a fixed reference point. Temperature is a measure of the average kinetic energy of particles, and negative infinity would not establish a well-defined baseline. Absolute zero provides a clear and universally agreed-upon reference point for temperature measurements.